Those who say keep it aren't wrong -- for them. For me, I would call, get a slip, and send it in. (All you need to send is the slide, which should expedite the service and return). Based on your picture, it is pretty cut and dried. You will get another one in no time.
S&W's are superb guns for the price, and possess the accuracy and reliability of guns that cost two or three times as much (and that some guns never achieve). I think you have to get into the essentially hand-built M1911's or other specialty guns, usually running $1500 or more, to achieve better practical accuracy -- that may be debatable, but its hard for a gun at any price to beat 100% reliability, which most M&Ps achieve out of the box. And S&W's are backed up by a great warranty and customer service program, which unfortunately you will probably validate in the near term.
Final thought: it may not bother you now, but if you ever go to re-sell this gun, say to switch calibers or for some other reason, the poor roll mark will detract from its value.